The present invention relates to the secure electrical supply of several electronic modules able to be brought together in the same rack and having several levels of criticality.
It applies in particular, but not exclusively, to the electrical supply of electronic equipment on board aircraft.
The electronic equipment mounted on board an aircraft is usually grouped together in racks and supplied, by way of one or more electrical energy distribution networks, by means of alternators driven by the engines propelling the aircraft and backed up by electrochemical accumulator batteries. The electrical power available on the electrical energy distribution networks of an aircraft depends on the generator used and requires management of the electrical power consumed as a function of the availabilities at the time. Certain events, such as a loss of engine power, startup of the propulsion engine(s) from the electrochemical accumulator batteries or else a partial failure at the level of the distribution networks, bring about a reduction in the electrical power available such that it is no longer possible to satisfy the energy requirements of all the attached electronic equipment. It is therefore necessary to make choices and to carry out load shedding of the electrical energy distribution networks, by cutting the supply to the electronic modules considered to be the least critical for the continuance of the mission. In view of this eventuality, the electronic equipment of an aircraft are classified according to several levels of criticality, usually three: critical, essential and normal, and connected to the electrical energy distribution networks by way of switches controlled by a load shedding management device to which are sent more or less severe load shedding commands depending on the instantaneous electrical power available.
The device for partitioning electrical energy of an electronic rack for an aircraft therefore usually encloses electrical partitioning wiring linking the electronic modules of the rack to one or more electrical energy distribution networks with outputs equipped with switches under the control of a device for managing load sheddings.
The aeronautical environment imposes particular constraints on an electrical energy partitioning device for an airborne electronic rack, in particular, reliability constraints which are especially severe as regards the system for managing load sheddings which, should there be a failure, must not give rise to untimely cuts in the supply to the equipment, weight constraints and modularity constraints. Specifically, an electrical energy partitioning device for an airborne electronic rack must be capable of being tailored at least expense, to the great diversity of levels of equipment which may be encountered on an aircraft, and to the changes due to the upgrading of this equipment as a result of the incessant advances in technology. To cope with this great diversity of levels of equipment and to ease the upgrading of the equipment, the trend is to use electronic modules with standardized dimensions and standardized connector engineering, specialized by functions, some of which form part of the original equipment of the aircraft and others of which are added subsequently, and to accommodate them, in rows in racks equipped with standardized backplane connectors.
The lightness constraints prompt the adoption, for the construction of the load shedding management system, of a single integrated circuit simultaneously delivering the control commands for all the switches controlling the individual branch-offs of the supplies to the electronic modules, this integrated circuit being, for example, a semi-custom or precharacterized ASIC (Application Specific Integrated Circuit) digital integrated circuit, the architecture of which is determined from a combination of precharacterized elementary cells. Such a circuit has the drawback of necessarily being complex since it must be designed for the maximum capacity of the rack in terms of electronic modules and to allow a maximum possibility of choice of criticality level for each electronic module of the rack. Due to its complexity, it encloses a large number of semiconductor elements, this raising reliability problems since the reliability of an electronic circuit is inversely proportional to the number of semiconductor elements that it contains.
The object of the present invention is a device for partitioning electrical energy between a plurality of electronic modules with possibility of load shedding guaranteeing a very considerable level of security despite the presence of a load shedding system.
Its object is also a device for partitioning electrical energy between a plurality of electronic modules, with possibility of load shedding, tolerating a change in the supplied electronic modules, in their number and in their criticality class whilst complying with a very high level of security.
Its subject is a device for partitioning electrical energy between a plurality of electronic modules disposed in an electronic rack, with possibility of several levels of load shedding, comprising an electrical supply line attached on the one hand to at least one electrical energy distribution network and on the other hand to the various electronic modules by way of breaker relays and means for managing the load sheddings instigating the commands for opening and closing the breaker relays as a function of load shedding control signals applied to the electrical energy partitioning device and corresponding to the desired level of load shedding. This electrical energy partitioning device is noteworthy in that the means for managing the load sheddings comprise:
a network partitioning load shedding commands with several parallel electrical conductors, equal in number to that of the desired levels of load shedding, each attached to a load shedding control input corresponding to a particular level of load shedding,
diode-type switches carrying out an xe2x80x9corxe2x80x9d-type logic function, equal in number to that of the breaker relays, each having an output attached to the control input of a breaker relay and inputs equal in number to that of the levels of load shedding, and
a tag strip interposed between the inputs of the diode-type switches and the parallel conductors of the network partitioning load shedding commands, making it possible to establish, with the aid of straps, connections between the inputs of each diode-type switch and the electrical conductors of the network partitioning load shedding commands as a function of the criticality levels allocated to the electronic module or modules supplied by way of the breaker relay whose control input is driven by the relevant diode-type switch.
Advantageously, the electrical energy partitioning device further includes electronic amplifying circuits which are interposed at input ahead of each of the conductors of the network partitioning load shedding commands and which operate in the disabled or saturated state in such a way as to pass or not pass a current through the diodes of the switches connected to their outputs by way of the conductors of the network partitioning load shedding commands and wired straps of the tag strip, and thus to control the open or closed states of the breaker relays disposed on the supply lines of the electronic modules.
Advantageously, the electronic amplifying circuits interposed at input ahead of the conductors of the network for partitioning load shedding commands are quipped with a contact relay interposed on their utput making it possible to subject the execution of a load shedding command to an additional condition such as the noting of a low electric voltage on the electrical energy distribution network or networks at the input of the rack.
Advantageously, the electronic amplifying circuits interposed at input, ahead of the conductors of the network for partitioning load shedding commands are equipped with a contact relay connecting their output to earth or to the potential of a bias source in such a way as to force the generation of a load shedding command in the presence of an additional condition such as the noting of an overly large electric current consumed by the rack.
Advantageously, the electronic amplifying circuits interposed at input ahead of each of the conductors of the network for partitioning load shedding commands include at least one transistor-based amplifier stage.
Advantageously, the electronic amplifying circuits interposed at input, ahead of each of the conductors of the network for partitioning load shedding commands include two transistor-based amplifier stages.
Advantageously, the electronic amplifying circuits interposed at input, ahead of each of the conductors of the network for partitioning load shedding commands include at least one transistor-based amplifier stage mounted in common emitter mode.
Advantageously, the electronic amplifying circuits interposed at input, ahead of each of the conductors of the network for partitioning load shedding commands have their inputs referred back when quiescent by a resistive circuit to a bias voltage urging them to a disabled or saturated state corresponding to an absence of load shedding command.
Advantageously, the electronic amplifying circuits interposed at input, ahead of each of the conductors of the network for partitioning load shedding commands include at input a contact relay open when quiescent, ordered to close by a load shedding command imposing a bias voltage on their inputs causing them to leave their quiescent state.
Advantageously, the device for partitioning electrical energy between a plurality of electronic modules disposed in an electronic rack is made in the form of a so-called xe2x80x9cTsupplyxe2x80x9d module which plugs into the electronic rack in the same way as the other electronic modules and which exhibits on its front edge, accessible from outside the rack, a plug-in submodule to which some or all of the straps of the tag strip are dropped.
Advantageously, in the case where the electronic modules to be supplied are provided with identifying means specifying their level of criticality, the electrical energy partitioning device is provided with an automaton analyzing the consistency between the load shedding levels assigned to the electronic modules such as they result from the configuration adopted for the wired straps of the tag strip and the levels of criticality of the electronic modules such as they ensue from the information provided by their identifying means.
Advantageously, the consistency analysis automaton controls a consistency indicator light.
Advantageously, in the case where the partitioning device is made in the form of a supply module which can be plugged into a rack, the consistency indicator light is placed on the front edge of the supply module, visible from outside the rack.
Advantageously, in the case where the partitioning device is made in the form of a supply module which can be plugged into a rack, with a plug-in submodule in its front face supporting some or all of the straps of the tag strip, the consistency indicator light is mounted on the front edge of the plug-in submodule.